FAILURE PREDICTION OF METALLURGICAL EQUIPMENT PARTS BY STRENGTH CRITERIA, MADE OF GREY CAST IRON, ON THE BASIS OF MICROSTRUCTURAL MODELLING OF STRESS STATE

Abstract

The article proposes a methodology for estimating the gamma-percent life of metallurgical equipment parts made of grey cast iron on the basis of micro structural modelling of its stress state, which is formulated using known relationships for estimating the average life of mechanical equipment parts by the criterion of kinetic strength, the linearisation method of random arguments allowing to estimate the variance of the function under study and tools of micro structural modelling of the stress state of the material. It allows at the stages of design and operation to take into account the all-round influence of loading conditions of the investigated technical object, its operating temperature, physical and mechanical characteristics of structural components of grey cast iron on gamma-percent resource. Its main distinctive features are mathematical dependences allowing estimating the value of dispersion of parameters necessary for calculation of resource characteristics, as well as the possibility of taking into account the anisotropy of the real structure of grey cast iron. In addition, the procedure of verification of the proposed methodology by comparing theoretically obtained values of gamma-percent resource with the value established in the normative and technical documentation is carried out. The spacer plate of SMD-110 jaw crusher, made of grey cast iron of GI-20 grade, is considered as an object of research physical and mechanical characteristics of its structural components, such as modulus of elasticity and Vickers micro hardness were experimentally evaluated using the method of instrumental indentation. The prediction error does not exceed 18%, which in turn confirms a sufficient level of reliability of the theoretical solutions proposed in this article, which can be used in the design of metallurgical equipment parts made of grey cast iron, as well as in the formation of the periodicity structure of its repairs.